116 MR. C. F. U. MEEK OX THE CORRELATION OF 



5. Elytra fully developed in both sexes. 



6. Mediastinal area of elytra gradually extended towards the apex, 



prolonged to length o£ anterior border and not lobulate at base. 

 Anterior border straight. 



7. Wings developed. 



8. Length of body, male 13-15 mm., female 20-24 mm. 



Stenobothrus bicolor. 



1. Very variable in colour. 



2. Antennae of equal length in both sexes. 



3. Pronotum with transverse furrow nearer to anterior than to posterior 



border. 



4. Lateral carinas of pronotum sharply angled in anterior part, diverging 



tow^ards anterior and posterior borders. 



5. Elytra fully developed in both sexes. 



■6. Mediastinal area of elytra extended abruptly towards the apex and 

 extended round base, forming a rounded lobule ; anterior margin of 

 elytra convex round base. 



7. Wings developed. 



8. Length of body, male 15-lG mm., female 19-24 mm. 



"Stexobothrus curtipexxis. 



1. Variable in colour. 



2. Antennae longer in male than in female. 



3. Pronotum with transverse furrow nearly in middle. 



4. Lateral carinse of pronotum straight and parallel. 



5. Elytra very short. 



6: Mediastinal area of elytra extended abruptly towards the apex and 

 extended round base, forming a rounded lobule ; anterior margin of 

 elytra convex round base. 



7. Wings very short in female ; in male equal in length to body. 



•8. Length of body, male 17*5 mm., female 17*5 mm. 



Let us now try to correlate these characters and the chromosome rod- 

 lengths of the respective complexes. We will firstly consider the lateral 

 carinse of the pronotum ; these are parallel or slightly approximating in 

 S. paraUelus, S. viridulus, and S. ciirtipennis, but sharply angled in S. hicolor. 

 This characteristic is distinctive, for Burr has pointed out that by it alone we 

 can distinguish the last-named from the other three species. Now if corre- 

 lation is evident, we nmst expect to find corresponding chromosomes of the 

 same length in S. paraUelus, S. viridulus, and S. curtipennis, but of a different 

 length in S. hicolor ; if, however, we follow the arrows in the diagram we see 

 that no long chromosome fulfils these conditions, and correlation is therefore 

 not established. 



